Machine for packaging goods

ABSTRACT

A machine for packaging goods having a central hole in a film, for example vehicle tires in a flexible film of plastics material. Film is unwound from a band of film on a bobbin by primary and secondary sets of grippers which grip longitudinal edges of the film and which are revolved to produce a tubular sheath of film. The sheath of film is then severed from the band. The set of grippers at one end of the sheath are moved to produce a cone of film from the sheath and the smaller end of the cone of film is caused to enter the central hole of the goods. The set of grippers of the smaller end are moved radially outwardly and the other set of grippers moved downwardly about the goods to encase the goods in the sheath of film. The now contacting and overlapping ends of the sheath of film are integrally joined e.g. by welding electrodes.

United States Patent 1191 Thimon Nov. 4, 1975 Assistant ExaminerJohn Sipos [75] Inventorggr: Thlmon Alx Les Bams Attorney, Agent, or FirmRobert E. Burns;

Emmanuel J. Lobato; Bruce L. Adams [73] Assignee: Societe dApplications Thermiques,

France 57 ABSTRACT [22] F'led: May 1974 A machine for packaging goods having a central hole [21] A L N 471,168 in a film, for example vehicle tires in a flexible film of plastics material. Film is unwound from a band of film on a bobbin by primary and secondar sets of gri ers [3O] Fore'gn Apphcauon Pnomy Data 1 which grip longitudinal edges of the film and \iiiiich May 17, 1973 France 73.17942 are revolved to produce a tubular sheath of film The sheath of film is then severed from the band. The set U.S. 3 of grippers at one end of the sheath are moved to pro- Int. C1.2 duee a cone of from the sheath and the smaller of Search end of the cone of is caused to enter the central hole of the goods. The set of grippers of the smaller References Cited end are moved radially outwardly and the other set of UNITED STATES PATENTS g ppers moved downwardly about the goods to en- 1,354,371 9/1920 Angier 53/204 x F the goods h the Sheath of mm The f 2,668,402 2/1954 Whytlaw 53/13 mg and Overlappmg ends of the sheath of film are 2,774,202 12/1956 Henry 53 204 X grally joined e.g. by welding e1ectrodes. 3,354,612 1 1/1967 Matsuoka 53/204 12 Claims, 7 Drawing Figures US. Patent Nov. 4, 1975 Sheet 1 of3 3,916,601

US. Patent Nov. 4, 1975 Sheet 2 of3 3,916,601

MACHINE FOR PACKAGING GOODS BACKGROUND TO THE INVENTION This invention relates to a machine for packaging goods having a central hole, particularly ring-shaped goods such as tires for motor vehicles for example, in a flexible film of a plastic substance.

A process is already known for packaging goods having a central hole in a section of tubular sheath in which one of the two end portions of the section of sheath is fitted around a spindle while the other end portion of the section of sheath is contracted and cut; the goods to be packaged are placed round the section of sheath along the contracted end until it rests on the spindle, the two end portions of the section of sheath are folded down over the outer face of the goods, so that they overlap, and finally, the two end portions are joined together where they overlap.

Due to its design, this process can only be used for articles of small dimensions such as eg wire spools.

The general object of the present invention is therefore to provide a packaging machine based on a variation of the above process, utilizing a band of film of a plastic substance instead of a section of tubular sheath, intended to package goods of larger dimensions than the above, and in particular, tires for motor vehicles.

SUMMARY OF THE INVENTION According to the invention there is provided a machine for packaging goods having a central hole, particularly ring-shaped goods such as tires for motor vehicles, in a flexible film of plastics material, said machine comprising means for feeding a band of said film and severing said band of film transversely, movable primary and secondary gripping means for gripping the band of film along its two longitudinal edges evenly distributed around a common symmetrical axis to produce an open-ended tubular sheath from the band of film around and parallel to said axis; a primary drive means to move the primary gripping means towards and away from said axis; a secondary drive means for effecting relative axial displacement of the primary gripping means in relation to means for holding the goods to be packaged; a tertiary drive for effecting relative axial displacement of the secondary gripping means in relation to the primary gripping means for bringing the former to bear against the latter, and means for joining the two end portions of the length of tubular sheath together while held about said goods by the primary and secondary gripping means respectively, whereby said goods are packaged in said film.

BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the invention will now be described by way of example, with reference to the accompanying drawings in which:

FIG. 1 shows a packaging machine according to the invention in section along its vertical axial symmetryplane;

FIG. 2 shows the machine in section on its horizontal plane along the line II-lI on FIG. 1; and

FIGS. 3,4,5,6 and 7 are diagrammatic part-represen tations showing the machine in section along its vertical axial symmetry-plane, at various successive stages of operation in accordance with the invention.

DESCRIPTION OF PREFERRED EMBODIMENT The drawings show a machine 1 for packaging goods 2 having a central hole 3, in particular ring-shaped goods such as tires for motor vehicles, the machine comprising a vertical frame 4, means 5 for feeding a band of film 6 and cutting it crosswise, movable primary and secondary means 7, 8 for gripping the band of film 6 along its two longitudinal edges and for annularly distributing said edges about a vertical axis 9 and enabling an open-ended tubular sheath to be formed from the band of film around and in parallel to the axis 9. A primary drive 10 is provided for moving the primary gripping means 7 to or from the axis 9. A secondary drive 11 effects relative axial displacement of the primary gripping means 7 in relation to holder means 12 for holding the goods 2. A tertiary drive 13 effects relative axial displacement of the secondary gripping means 8 in relation to the primary gripping means 7 so as to bring the one to bear upon the other. Means 14 are provided for joining together the two end portions of the length of tubular sheath held by the primary and secondary gripping means 7 and 8, respectively.

The packaging machine 1 shown in the Figures is set up vertically and the goods 2 to be packaged are introduced gradually into the machine at its lower end by an insertion device 15. The section of FIG. 1 is taken along the axial vertical symmetry-plane 16 of the machine.

The frame 4 is generally in vertical parallelpiped form and includes a horizontal base 17 to which vertical sills 18 are fixed, to which the protective panels 19 are fixed, preferably in demountable'fashion so as to give access to the various mechanisms of the machine. There is a gap between the lower edge of the protective panels 19 and the base 17 so as to allow the goods 2 to be packagedto be introduced into the machine 1.

The means 5 for feeding the film 6 and effecting a crosswise cut comprise an axle or vortex 20 with a vertical axis fixed to the frame 4, around which a bobbin 21 of film is allowed to rotate freely and from this the band of film 6 is extracted, the end part of which is held by a movable holding facility 22 to which a cutting device 23 is fixed. The holding facility 22 takes the form of a vertical frame 24 able to pivot around a vertical shaft 25 fixed to the frame, by means of a pneumatic ram 26, or any other similar mechanism, to which two wheels 27 with vertical axes are fixed and between which the end part of the band of film is engaged and retained. The cutting device 23 is fixed vertically to the frame 24 near to the wheels 27'. The cutting device is in the form of a knife or, in the case of a film of plastics material, a hot wire.

The primary gripping means 7 are located more or less at the same level as the lower end of the bobbin 21 of film and above the lower edge of the protective panels 19. They comprise several radial arms 28 distributed regularly about the axis 9, swingably joined to a first hub 29 fixed at the lower end of a hollow axle 30, following the axis 9, and provided at their free ends with gripping devices 31 to grip the film such as points, claws or clamps.

The arms 28 are joined to the hub 29 in such a way that their outer ends can be moved from or to the axis 9 by the primary drive 10 described subsequently. In the spread position of the arms 28 shown in FIG. 1, the gripping devices 31 lie at a distance a from the axis 9 which is greater than the maximum radius b of the 3 goods 2. In this position, the arms 28 lie at the same level as the lower longitudinal edge of the band of film 6.

The primary drive comprises a second or movable hub 32 fixed at the lower end of a grooved axle 33 mounted in sliding fashion in the hollow axle and projecting from the latter axle at both ends; connecting links or members 34, in equal number to the arms 28, are each jointed at one end to the movable hub 32 and at the other end to an arm 28 at a knuckle-joint 35 in the proximity of the first hub 29. The primary drive 10, lastly, comprises a pneumatic ram 36, or similar device, placed vertically above the frame 4 and acting on the grooved axle 33 in such a way as to move this axle vertically upwards or downwards without, however, impeding its movement with the hollow axle 30. For this purpose, the piston of the ram 36 is equipped with a bearing 37 in which a roller 38 fixed at the upper end of the grooved axle 33 is allowed to rotate freely. It is clear that movement of the movable hub 32 along the axis 9 enables the arms 28, as will be seen subsequently, to be moved away from or conversely approximated to the axis 9.

The secondary gripping means 8 comprise a bell 39 fixed to a sleeve 40 prevented from rotating and free to slide axially along the hollow axle 30. For this purpose the axle 30 includes an axial projection 41 cooperating with a groove within the sleeve or, inversely, the sleeve is provided with a projection cooperating with a groove in the hollow axle 30.

The lower, free, circular edge of the bell 39 is equipped with gripping devices 42 to grip the film, such as points, claws or clamps, spaced evenly from each other about the axis 9. The internal radius 0 of the bell 39 is greater than the maximum radius b of the goods 2 so as to be able to cap the latter as will be seen subsequently.

The secondary gripping means 8 move in sliding fashion along the hollow axle 30 between two end positions, namely an upper end position shown in FIG. 1 where the gripping devices 42 lie at the same level as the upper longitudinal edge of the band of film 6, and a lower end position shown in FIG. 7 where the bell 39 rests on the spread arms 28.

The means 14 for joining the two end portions of the length of tubular sheath formed by the primary and secondary gripping means 7 and 8 from the band of film, comprise a horizontal disc 43, concentric with the axis 9, located above the bell 39 and extended upwards by i a sleeve 44 fixed so as to rotate about the axle 30 and free to slide axially along the axle, and devices 45 to join the two end portions of the length of tubular sheath together fixed about the edge of the disc 43, spaced evenly from'each other about the axis 9, and directed vertically downwards about the bell 30. These joining devices comprise, for example, heating electrodes enabling the film to be welded by heat. The sleeve 44 is supported by a horizontal bracket 46, which will be referred to subsequently, and is able to pivot in relation to this bracket by means of e.g. a ball bearing 47. The disc 43 and the lower part of the sleeve 44 are respectively pierced and hollowed, thereby forming a housing 48 into which the sleeve 40 forming part of the secondary gripping means 8 lodges relatively forcefully under the impetus of a compression spring 49 hearing at one end on the lower face of the disc 43 and at the other end on a flange on the sleeve 40 to which the bell 39 is fixed. Vertical guidance tubes 50 are fixed to the outside face of the cylindrical side wall to the bell 39 in a number equal to that of the joining devices 45 and in these the said devices slide when the sleeve 44 is moved axially in relation to the sleeve 40. This cooperation between the joining devices 45 and the guidance tubes 50 ensures rotary movement to the joining devices 14 by the secondary gripping means 8. Provision should preferably be made of supplementary blocking devices fixed on the one hand to the joining devices 45 and on the other hand to the guidance tubes 50, restricting movement of the disc 43 and the bell 39.

When the joining devices 45 are in the form of heating electrodes, conducting wires 51 are provided connecting each of these electrodes to a collector 52 fitted round the sleeve 44 and supplied with electrical current by an electrical conductor wire 53 connected up to an electricity supply cupboard 54.

The tertiary drive 13 is intended simultaneously to move the secondary gripping means 8 and the joining means 14 in between their two end positions referred to above and comprises a vertical guidance column 55 along which the bracket 46 is fitted in sliding fashion, and a vertical threaded axle 56 passing through a tapped hole in the bracket 46, and which is given rotary movement by an electric motor 57 by means of two pulleys 58a and 58b which are fixed respectively to the axle of the motor 57 and the threaded axle 56, and of a belt 59 stretched between the two pulleys 58a and 58b.

The electric motor 57 located at the upper end of the frame 4 is connected to the electricity cupboard 54. The frame 4 preferably includes a horizontal shelf 60 located halfway up approximately at the same level as the disc 43 when the joining means 14 are extended to their lowest position. The horizontal shelf 60 carries a bearing for the threaded axle 56. The natural consequence of the preceding description is that the tertiary drive 13 enables relative axial displacement to be effected of the secondary gripping means 8 in relation to the primary gripping means 7, and also a relative axial displacement of the joining means 14 in relation to the primary gripping means 7.

The holding means 12 comprise two horizontal arms 61a and 61b symmetrically opposed in relation to the plane 16 and hinged to a horizontal transom or bracket 62 at right angles to the plane 16 about the vertical articulation axes 63a and 63b, and a facility 64 acting on the two arms 61a and 61b in order to space or conversely to approximate them from or to each other. This facility 64 includes at least one draw-spring 65 attached to the two arms 61a and 61b at a predetermined distance from the two axes 63a and 63b, and two vertical rollers 66a and 66b stretching between the horizontal shelf 60 and the means of insertion l5, fitted so as to rotate freely around their respective axes and connected to each other at their two ends by an upper horizontal strut 67 and a lower horizontal strut 68 fixed respectively at the lower end of a vertical shaft 69 free to rotate in a bearing set in the horizontal shelf 60, and at the upper end of a shaft 70 free to rotate in a bearing set in the base 17. Finally, the facility 64 includes a drive device 71 for moving the unit comprising the two rollers 66a and 66b and the struts 67 and 68 between two positions at of each other, in the first of which, shown in FIG. 2, the rollers 66a and 66b lie in the plane 16 and in the second of which these two rollers are symmetrical with each other in relation to the said plane. This drive device 7B is in the form of a pneu- 74a and 74b.

: facility.

of whose matic rarn at the free end piston a connector fixed tothe shaft 70 is joined. This pneumatic ram and the pneumatic rams 26 and 36.referred to above are all the two axes 63a and 63b, and move the two arms in opposite directions against the compression spring. To ensure symmetrical opening. and closing of the two arms 61a and 61b provision is preferably made of two cog-wheels 73a and 73b engaging with each other and fixed respectively on the two axes'63a and 63b.

in the embodiment of the machine illustrated the secondary drive means 11 act only on the holding means 12 so as to move them vertically upwards or downwards in order to approximate them to, or conversely, to withdraw them from the primary gripping means 7. These secondary drive means include two vertical guidance columns 74a and 74b in symmetry with each other in relation to plane 16 and fixed at one end to the base 17 .and at the other endto the horizontal shelf 60, and

along these the horizontal transom 62 slides.

A threaded vertical axle 75 having the same axis as theaxle 56 and lying in the plane 16 is fixed so as to pivot between the end stops fixed respectively to the base 17 and to the horizontal. shelf 60, and passes through a tapped hole in the transom 6:2. This threaded axle 75 is rotated by an electric motor 76 fixed to the base 17 by means of two pulleys 77a and 77b fixed respectively to the axle of i the motor 76 and to the threaded axle 75 of a transmission belt 78 stretched between the two pulleys 77a ,and 77b. The motor 76 is be seen subsequently. The use of the rollers 66a and 66b ensures that the arms openor, conversely, close whatever their position along the guidance columns .The means for inserting the are located above the base 17 and are formed by a moving plate, a-

roller conveyor, or a conveyor belt, or any other similar The machine further includes an electric motor 79 at its'upper end connected by electrical conductor wires to the electricity cupboard 54 and rotating the hollow axle 30 and thereby the grooved axle 33 and,on the one hand the primary grippingmeans and on the other hand the secondary gripping means 8 and the joining means 14. A toothed wheel is fixed to the axle of the motor 79 and by means of a chain 80 drives another toothed wheel 81 fixed to the hollow axle 30. The hollow axle is supported .by a bearing 82 fixed permanently so as to prevent axial movement relative to the upper part of the frame 4 and allowing the axle to rotate while preventing it from sliding axially.

The machine described above may be subject to many variations remaining within the scope of the in- 'three connected up to the pneumatic cupboard 72.

vention claimed and relating in the first place to the position of the machine, in the second plate to the nature of the devices making up the machine, and in the third place to the relative placing of the devices in relation to each other.

The machine may therefore beset uphorizontally, 8 instead of vertically as in'the embodiment described and shown. 7 r 7 Many mechanisms in the machine may be replaced by equivalent devices, namely the pneumatic ram 36, the bearing 37 and the roller 38, the gripping devie es 31 and 42, the joining devices 45, the guidance tubes 50, the threaded axle 56, the horizontal arms 61a and 61b, the unit comprising the two rollers 66a and 6612, the two struts 67 and 68, the threaded axle 75, and the bearing 82. More generally, the primary gripping means 7, the secondary gripping means 8, theprimary drive 10, the secondary drive 11, the holding means 12, the tertiary drive 13, the joining means 14, and the insertion device 15 may be executed differently from those described above.

Finally, the arrangement of the various mechanisms in relation to each other and their movement may similarly be the subject of variation. The goods to be packaged may therefore be introduced to the upper end of the section of tubularsheath and notat the lower. This introduction may be effected not by moving the goods round the bobbin 21 is hooked to the holding facility 22 located close to the bobbin 21. j

The bell 39 being in the upper end position and the arms 28 being spread, the pneumatic ram 26 is operated to bring the end portion of the band 6 into contact with the gripping devices'31 and 42.

The motor 79 is started up in such a way as to cause the hollow axle 30 to rotate and consequently the primary' and secondary gripping means 7 and '8until the latter have made one circuit enabling an openlength of tubular sheath to be formed progressively parallel to the axis 9. The cutting device 23 is operated to separate the length formed from the band rolled round the bobbin 21(FIG. 3).

The pneumatic ram 36 is operated to separate the hubs 29 and 32 soas to cause the arms 28 to pivot downwards toward axis 9. In the course of this movement the length of sheathis pulled vertically downwards and for this purpose the secondary gripping means 8 andthe joining means 14 are moved vertically downwards by the motor 57 coupled to the screw 56. The machine is then in the position shown in FIG. 4.

The arms 61a and 61b being brought to bear on the goods 2 to be packaged by virtue of the two rollers 66a and66b lying in the plane 16, the transom 62, and

therefore the goods 2, are moved vertically upwards by operating themotor 76. v

In the course of this movement, the arms 28 having had their outer ends moved toward the axis 9 then have a reduced radial displacement d, whereby they are made to penetrate the central hole 3 having radius e' so as to bring the goods into the position illustrated in FIG. 5.

The arms 28 are then displaced through the action of the pneumatic ram 36 so as to come to bear below the goods and supporting them. By operating the drive device 71 both arms 61a and 61b are moved outwards against the spring 65 by means of the two rollers 66a and 66b.

The goods 2 resting on the arms 28, the arms 61a and 61b are returned to their original position, FIG. 6.

The motor 57 is started up so as to move the secondary gripping means 8 and the associated joining means 14 vertically downwards until the bell 39 comes to rest on the anns 28.

The machine is then in the position shown in FIG. 7.

The length of tubular sheath held on the one hand by the gripping devices 31 and on the other hand by the gripping devices 42 thereupon covers the external surface of the goods 2. The spring 49 being compressed, the joining devices 45 are applied firmly to the arms 28, the two end portions of the length of tubular sheath being applied to each other and being joined together by electrodes.

The ram 36 and the motor 57 are then operated in such a way as to move the bell 39 vertically upwards and to turn the arms 28 downwards in the direction of the axis 9, thereby freeing the packaged goods 2 which, by virtue of their own weight, fall onto the insertion means from which they are then removed.

I claim:

1. A machine for packaging ring-shaped articles, comprising;

holding means for holding a ring-shaped article having a central hole;

means for feeding a band of flexible packaging film material from a supply of such material and for severing said band transversely from said supply;

movable primary and secondary gripping means for gripping the band along two longitudinal edges thereof and for disposing the severed band and its edges annularly around an axis to produce a tubular sheath parallel to and around said axis and to provide said sheath with open ends defined by the annularly disposed edges of the band;

a primary drive means for retumably moving the primary gripping means towards said axis to reduce the diameter of the respective open end of the sheath;

a secondary drive means for effecting relative axial displacement of the holding means in relation to the primary gripping means and for thereby displacing the primary gripping means, with the open sheath of reduced diameter held thereby, through the central hole of the article;

a tertiary drive means for effecting relative axial displacement of the secondary gripping means in relation to the primary gripping means, pursuant to return moving of the primary gripping means displaced through the central hole, to bring one of the gripping means around the article and against the other gripping means with the respective ends of the sheath held thereby; and

means for thereupon joining the two ends of the sheath together, whereby the article is packaged in said film material and the central hole is left free of such material extending across the same.

2. A machine as claimed in claim 1, wherein the primary gripping means comprise; a number of arms set evenly apart from each other radially about said axis; a hub concentric about said axis means for hingedly joining inner ends of said arms, adjacent said axis to said first hub; and means at outer ends of said arms for gripping the film material.

3. A machine as claimed in claim 2, wherein the primary drive means comprises; a second hub concentric about said axis; means for hingedly connecting the second hub to the arms; and means for relative axial displacing of the second hub in relation to the first hub.

4. A machine as claimed in claim 3, wherein the means for relative axial displacing of the second hub in relation to the first hub comprises; a hollow axle having one end supporting the first hub; a grooved axle slidably mounted in the hollow axle and having an end supporting the second hub; and means for relative axial displaceing of the two axles and of the respective hubs in relation to each other. i

5. A machine as claimed in claim 4, wherein the secondary gripping means comprise; a bell concentric about said axis and having a free edge; and film gripper devices spaced evenly from each other along said edge.

6. A machine as claimed in claim 5, wherein said means for joining the ends of the sheath comprise film joining devices spaced evenly from each other along said edge of the bell and located between the film gripper devices of the secondary gripping means.

7. A machine as claimed in claim 6, wherein said holding means comprise; two holding arms both hinged at respective ends about axes parallel to said axis; resilient means for permanently biasing the two holding arms towards each other; and means for acting on the two holding arms to separate them from each other against the bias of said resilient means.

8. A machine as claimed in claim 7, wherein said means for acting on the two arms comprise; a unit of two cylinders rotatable about respective axes parallel to said axis; struts supporting said cylinders; shafts parallel to said axis and pivotally supporting said struts; and means for acting upon said shafts to cause the unit of the two cylinders to pivot between a primary position where the two cylinders lie in a symmetrical plane of the two arms and are held close to each other by the resilient means to engage the article, and a secondary position where they lie symmetrically to eachother in relation to said symmetrical plane 'more remote from each other to release the article.

9. A machine as claimed in claim 1, including a bracket supporting the secondary gripping means and the joining means and mounted slidably parallel to said axis.

10. A machine as claimed in claim 4, including means for mounting the'secondary gripping means slidably on the hollow axle and for preventing the secondary gripping means from pivoting about the hollow axle.

11. A machine as claimed in claim 10, further including motor means for rotating the hollow axle and thereby the primary gripping means, the secondary gripping means, and the means for joining the ends of the sheath.

12. A machine as claimed in claim 7, including support means for supporting the two holding arms and column means parallel to said axis for slidably supporting the support means. 

1. A machine for packaging ring-shaped articles, comprising; holding means for holding a ring-shaped article having a central hole; means for feeding a band of flexible packaging film materIal from a supply of such material and for severing said band transversely from said supply; movable primary and secondary gripping means for gripping the band along two longitudinal edges thereof and for disposing the severed band and its edges annularly around an axis to produce a tubular sheath parallel to and around said axis and to provide said sheath with open ends defined by the annularly disposed edges of the band; a primary drive means for returnably moving the primary gripping means towards said axis to reduce the diameter of the respective open end of the sheath; a secondary drive means for effecting relative axial displacement of the holding means in relation to the primary gripping means and for thereby displacing the primary gripping means, with the open sheath of reduced diameter held thereby, through the central hole of the article; a tertiary drive means for effecting relative axial displacement of the secondary gripping means in relation to the primary gripping means, pursuant to return moving of the primary gripping means displaced through the central hole, to bring one of the gripping means around the article and against the other gripping means with the respective ends of the sheath held thereby; and means for thereupon joining the two ends of the sheath together, whereby the article is packaged in said film material and the central hole is left free of such material extending across the same.
 2. A machine as claimed in claim 1, wherein the primary gripping means comprise; a number of arms set evenly apart from each other radially about said axis; a hub concentric about said axis; means for hingedly joining inner ends of said arms, adjacent said axis to said first hub; and means at outer ends of said arms for gripping the film material.
 3. A machine as claimed in claim 2, wherein the primary drive means comprises; a second hub concentric about said axis; means for hingedly connecting the second hub to the arms; and means for relative axial displacing of the second hub in relation to the first hub.
 4. A machine as claimed in claim 3, wherein the means for relative axial displacing of the second hub in relation to the first hub comprises; a hollow axle having one end supporting the first hub; a grooved axle slidably mounted in the hollow axle and having an end supporting the second hub; and means for relative axial displaceing of the two axles and of the respective hubs in relation to each other.
 5. A machine as claimed in claim 4, wherein the secondary gripping means comprise; a bell concentric about said axis and having a free edge; and film gripper devices spaced evenly from each other along said edge.
 6. A machine as claimed in claim 5, wherein said means for joining the ends of the sheath comprise film joining devices spaced evenly from each other along said edge of the bell and located between the film gripper devices of the secondary gripping means.
 7. A machine as claimed in claim 6, wherein said holding means comprise; two holding arms both hinged at respective ends about axes parallel to said axis; resilient means for permanently biasing the two holding arms towards each other; and means for acting on the two holding arms to separate them from each other against the bias of said resilient means.
 8. A machine as claimed in claim 7, wherein said means for acting on the two arms comprise; a unit of two cylinders rotatable about respective axes parallel to said axis; struts supporting said cylinders; shafts parallel to said axis and pivotally supporting said struts; and means for acting upon said shafts to cause the unit of the two cylinders to pivot between a primary position where the two cylinders lie in a symmetrical plane of the two arms and are held close to each other by the resilient means to engage the article, and a secondary position where they lie symmetrically to each other in relation to said symmetrical plane more remote from each other to release the article.
 9. A machine as claiMed in claim 1, including a bracket supporting the secondary gripping means and the joining means and mounted slidably parallel to said axis.
 10. A machine as claimed in claim 4, including means for mounting the secondary gripping means slidably on the hollow axle and for preventing the secondary gripping means from pivoting about the hollow axle.
 11. A machine as claimed in claim 10, further including motor means for rotating the hollow axle and thereby the primary gripping means, the secondary gripping means, and the means for joining the ends of the sheath.
 12. A machine as claimed in claim 7, including support means for supporting the two holding arms and column means parallel to said axis for slidably supporting the support means. 